Stop motion device for sewing machines



I Oct. 30, 1945. E. vossEN 2,337,953

STOP MOTION DEVICE FOR SEWING MACHINES Original Filed Fb. 12. 1944 T g3 7 7a 2" 75 IN VEN TOR.

Epwmeo Mme/v ArroIeNZ-x Patented Oct. 30, 1945 STO'P MOTION DEVICE FOR SEWING MACHINES Edward Vossen, Brookl yn, N. Y., assignor to Stop- Motion Devices Corporation, Brooklyn, N. Y., a corporation of New York Original application Fe 522,061. Divided and this 23, 1945, Serial No. 579,410

bruary 12, 1944, Serial No.

application February 6 Claims. (01. 112-219) This is a divisional application of Serial No. 522,061, filed on Feb. 12, 1944, for Stop motion devices for sewing machines.

This invention relates to new and useful improvements in stop motion devices for sewing machines, and is particularly intended for automatic sewing machines where one operator takes care of a group of machines. Of course, the invention is also valuable for a sewing machine Worked on by one operator.

It is intended that the new and improved stop motion device be used in combination with a sewing machine having a needle thread interlocking with a bobbin thread. The stop motion device is for detecting whether or not the needle thread is properly interlocking with the bobbin thread. This indirectly detects whether or not the bobbin thread has broken, or is exhausted, or whether there is some defect in the sewing machine which prevents the lock stitches from forming.

The invention proposes to so construct the stop motion device that it may be applied to various types and kinds of sewing machines. For example, to the usual one needle sewing machine, or machines having more than one needle operating at the same time, and producing any type of lock stitches. It is also applicable to machines having various kinds of pressure feet.

The new and improved stop motion device in accordance with this invention is characterized by a contact lever which is pivotally mounted and which is provided with a horizontally disposed front arm extending forwards -to a point slightly above and slightly back of the point where the needle or needles of the sewin machine are 'sewing and which is also provided with a back arm for moving against a spring contact when the front arm is lifted by the needle thread because of failure to lock with the bobbin thread.

The invention proposes a certain construction of the spring contact, and a certain way of supporting it in position. The arrangement insures a clean contact because the contacting parts are continuously wiping each other.

The invention also proposes a new and improved wayfor supporting the contact lever so that it may be set,in relation to the sewing point of the sewing machine, toa position in which the stop motion device acts best.

An important advantage gained by the new stop motion device, is that it will be sensitive to all kinds and types of threads, sewing under various kinds of conditions. Should the threads be light and weak, the stop motion will work just as satisfactorily as if they were heavy and strong.

All sewing machines have a certain amount of vibration. The new stop motion device is not sensitive to vibration, and will not stop the sewing machine because of vibration.

The invention also proposes the construction of a stop motion device as briefly explained which is simple, eflicient, and which may be manufactured and sold at a low cost.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawing, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure:

Fig. 1 is a fragmentary front elevational view of a sewing machine equipped with a stop motion device constructed in accordance with this invention.

Fig. 2 is a fragmentary side view of the machine shown in Fig. 1.

Fig. 3 is a fragmentary enlarged sectional view taken on the line 3-3 of Fig. 1.

Fig. 4 is a horizontal sectional view taken the line 4-4 of Fig. 3.

Fig. 5 is a fragmentary vertical sectional view taken on the line 5-5 of Fig. 3.

The stop motion device for sewing machines, in accordancewith this invention, is shown applied to a sewing machine In which may be stopped by an electric controller not shown on the drawing. The particular sewing machine I0 has two needles H and a pressure foot l2 consisting of two pressure foot sections spaced laterally of each other. The sewing machine II] as illustrated on the drawing is operating upon a strip of cloth material [3. The sewing machine is also provided with the usual reciprocating knife M which splits the strip l3 into two sections, during the sewing operation while the needles ll sew along the adjacent edges of the split sections. Thesewing machine I0 may be of any design and construction provided it has one or more needle threads 20 interlocking with bobbin threads 2|, see particularly Fig. 3, and interlocking at the point or points where the needles passes through the material being sewn.

A bracket 10 is attached to the head of the sewing machine I0. A vertical rod 63 is adjustably mounted upon the bottom end of the bracket 10, and is held in selected adjusted positions with screws 'Il engaging through said bracket and abutting the side of the rod 63. This vertical rod 63 is at a location in. back of the pressure foot l2 of the sewing machine.

A foot 62 is fixedly mounted upon the bottom end of the vertical rod 63. An insulation block 68 is mounted upon the rod 63 at a point above said foot 62. This insulation block 68 is held in position with several screws 50.- A spring contact 61 is mounted on the insulation block 68. This spring contact 61 is in the nature of a leaf spring. It is of U-shape when viewed from the top. It is attached by several small screws 5| to the insulation block 68. The side arms of the contact spring 61 extend forwards to the sides of the rod 63. The tips 52 of the side arms of the contact spring 61 are bent rearwards and towards each other; forming a jaw-like portion into which a contact 66 may engage.

The contact 66 is mounted upon a rear arm 65 of a contact lever 60 which is pivotally supported by a pintle pin 6| on said foot 62. The contact lever 60 extends forwards to a point slightly above and slightly back of the point where the needle 'or needles of the sewing machine are sewing. A relatively wide plate 12 is mounted upon the front arm of the contact lever 60 and extends.

over the stitches being sewn by the needles I I.

An open bottom casing 64 is disposed upon the bottom portion of the rod 63 and extends over and encases the contact '65 and contact spring 61. The casing 64 engages the sides of the foot 62 and is mounted on said foot 62 with several fastening elements 56. An electric wire 69 connects with the contact spring 61 and extends up through an opening in the casing 64 and is intended to be connected in the electric circuit of the controller, not shown, for the sewing machine.

and dash line position 60' and then the contact 66'will assume the position 66 and will engage the jaw portion 52 of the spring 61. When the 'needle'thread 20 ceases to interlock with the.

bobbin thread 2|, and the sewing -machines'keep operating, the thread 29 will soon reach a position as illustrated by thedot and dash 1ines'20. In Fig. 3 'referen'ce'numeral 1'3 'indicates'the' bed of the sewing machine 10 which is provided with a bobbin covering the plate 14 having an opening 15 through which the needle 'H passes during the sewing operation;

The operation of the device is as follows:

In the event that the needle thread or threads 26 cease interlocking with the bobbin threads '21, the needle thread or threads soon reach the position indicated by the dot and dash lines 20 in Fig. 3. This occurs eachtime that the needle or needles ll move upwards. The inclined needle thread 20, soon strikes the plate I2, and throws the lever 60 upwards so that the contact 68 moves towardsand engages the jaw portion 52 of the spring contact 61. This closes the controller circuit not shown on the drawing, from the lead 69 to the ground of the sewing machine, and the controller then acts to stop the sewing machine.

It is pointed out that sewing machines come with various kinds of pressure feet. A single needle sewing machine usually has merely an aperture in the pressure foot through which the needle passes. A pressure foot of this kind must The lever 60 is capable of being moved, or thrown upwards, to the 'dot be slotted from the aperture rearwards to prevent the pressure foot from holding the needle thread down, o that the needle thread may assume the inclined position 20, as illustrated in Fig. 3.

An important feature of the invention resides in the fact that the contact lever 60 is pivoted. For this reason, it may be moved without requiring any great force. There'is no need for flexing or bending the contact lever, to set off the stop motion device. For this reason it is possible to use very thin or weak threads on the sewing machine, and the stop motion device will operate properly.

Another feature, resides in the fact that the contact 66 will continuously wipe the jaw portion 5.2'of the contact spring 61, keeping it clean so that there is a good contact. The set screws H may be loosened, and the rod 63 adjusted upwards, or downwards for setting the plate 12 at a proper elevation for the operation of the lever 65] for different kinds of thread. The casing 64 protects and shields the contact 66 and spring contact 61.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

1'. A stop motion device for a sewing machine, comp-rising a bracket for attachment on the head of a sewing machine, a vertical rod adjustably mounted on said bracket at a position in back of the pressure foot of said sewing machine, a foot mounted on said vertical rod, an insulation block mounted on said rod at a point above said foot, 2. spring contact mounted on said insulation block, and a contact lever pivotally mounted on said foot and having a horizontally disposed front arm extending forwards to a point slightly above and slightly back of the point where the needle or needles of the sewing machine are sewing and having a back arm for moving against said spring contact when said front arm is lifted by, the needle threads because of failure to lock withthe bobbin threads.

2. A stop motion device fora sewing machine, comprising a bracket for attachment on the head of a sewing machine, a vertical rod adjustably mounted on said bracket at a position in back of the pressure foot of said sewing machine, a foot mounted on said vertical rod, an insulation block mounted on said rod at'a point above said foot, a spring contact mounted on said insulationblock, and a contact lever pivotally mounted on said foot and having a horizontally disposed front arm extending forwards to a point slightly above and slightly back of the point where the'needle or needles of the sewing machine'are sewing and havinga back arm for moving against said'spring contact when said front arm is lifted by the needle threads because of failure to lockwith the bobbin threads," said vertical rodbeing vertically slidably mounted in an openinginsaid bracket, and set screws forholding said rodinsaidade justable positions. e I r 3. A stop motion device for a sewing'machine, comprising abracket'for attachment on the head. of a sewing machine, a vertical-rod adjustably mounted on said'bracket at a position in back of mounted on said rod at a point above said foot,

a spring contact mounted on said insulation block, and a contact lever pivotally mounted on said foot and having a horizontally disposed front arm extending forwards to a point slightly above and slightly back of the point where the needle or needles of the sewing machine are sewing and having a back arm for moving against said spring contact when said front arm is lifted by the needle threads because of failure to lock with the bobbin threads, said spring contact being bent around said rod and being attached at its back onto said insulation block, and the tips of the front ends of said spring contact being directed inwards and towards each other for forming a jaw-like portion into which said contact lever may engage.

4. A stop motion device for a sewing machine, comprising a bracket for attachment on the head of a sewing machine, a vertical rod adjustably mounted on said bracket at a position in back of the pressure foot of said sewing machine, a foot mounted on said vertical rod, an insulation block mounted on said rod at a point above said foot, a spring contact mounted on said insulation block,

and a contact lever pivotally mounted on said foot and having a horizontally disposed front arm extending forwards to a point slightly above and slightly back of the point where the needle or needles of the sewing machine are sewing and having a back arm for moving against said spring contact when said front arm is lifted by the needle threads because of failure to lock with the bobbin threads, said spring contact being bent around said rod and being attached at its back onto said insulation block, and the tips of the front ends of said spring contact being directed inwards and towards each other for forming a jaw-like portion into which said contact lever may engage, and said contact lever being provided with a contact engageable into said jaw-like portion.

5. A stop motion device for a sewing machine, comprising a bracket for attachment on the head of a sewing machine, a vertical rod adjustably mounted on said bracket at a position in back of the presser foot of said sewing machine, a foot mounted on said vertical rod, an insulation block mounted on said rod at a point above said foot, a spring contact mounted on said insulation block, a contact lever pivotally mounted on said foot and having a horizontally disposed front arm extending forwards to a point slightly above and slightly back of the point where the needle or needles of the sewing machine are sewing and having a back arm for moving against said spring contact when said front arm is lifted by the needle threads because of failure to lock with the bobbin threads, and a relatively broad plate mounted upon the front end of said front arm for being engaged by said needle threads.

6. A stop motion device for a sewing machine, comprising a bracket for attachment on the head of a sewing machine, a, vertical rod adjustably mounted on said bracket at a position in back of the pressure foot of said sewing machine, a foot mounted on said vertical rod, an insulation block mounted on said rod at a point above said foot, a spring contact mounted on said insulation block, a contact lever pivotally mounted on said foot and having a horizontally disposed front arm extending forwards to a point slightly above and slightly back of the point where the needle or needles of the sewing machine are sewing and having a back arm for moving against said spring contact when said front arm is lifted by the needle threads because of failure to lock with the bobbin threads, and a casing disposed about the bottom of said rod and extending over and covering said contact spring and the contact arm of said contact lever and being mounted upon said foot.

EDWARD VOSSEN. 

